U.S. patent application number 14/628562 was filed with the patent office on 2015-06-18 for providing remote blue phosphors in an led lamp.
The applicant listed for this patent is SORAA, INC.. Invention is credited to Thomas M. Katona, Michael Ragan Krames.
Application Number | 20150167909 14/628562 |
Document ID | / |
Family ID | 52683223 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150167909 |
Kind Code |
A1 |
Katona; Thomas M. ; et
al. |
June 18, 2015 |
PROVIDING REMOTE BLUE PHOSPHORS IN AN LED LAMP
Abstract
Light emitting devices and techniques for using remote blue
phosphors in LED lamps are disclosed. An LED lamp is formed by
configuring a first plurality of n of radiation sources to emit
radiation characterized by a first wavelength, the first wavelength
being substantially violet, and configuring a second plurality of m
of radiation sources to emit radiation characterized by a second
wavelength, the second wavelength also being substantially violet.
Aesthetically-pleasing white light is emitted as the light from the
radiation sources interacts with various wavelength converting
materials (e.g., deposits of red-emitting materials, deposits of
yellow/green-emitting materials, etc.) including a blue-emitting
remote wavelength converting layer configured to absorb at least a
portion of the radiation emitted by the first plurality of
radiation sources. The remote wavelength converting layer emits
wavelengths ranging from about 420 nm to about 520 nm.
Inventors: |
Katona; Thomas M.; (San
Carlos, CA) ; Krames; Michael Ragan; (Mountain View,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SORAA, INC. |
Fremont |
CA |
US |
|
|
Family ID: |
52683223 |
Appl. No.: |
14/628562 |
Filed: |
February 23, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13856613 |
Apr 4, 2013 |
8985794 |
|
|
14628562 |
|
|
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61625592 |
Apr 17, 2012 |
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Current U.S.
Class: |
362/84 |
Current CPC
Class: |
F21Y 2105/16 20160801;
F21Y 2113/13 20160801; F21Y 2105/12 20160801; F21Y 2115/10
20160801; F21K 9/64 20160801 |
International
Class: |
F21K 99/00 20060101
F21K099/00 |
Claims
1. An LED lamp comprising: a first plurality of n radiation sources
configured to emit radiation characterized by a first wavelength,
the first wavelength being substantially violet; a second plurality
of m radiation sources configured to emit radiation characterized
by a second wavelength, the second wavelength being substantially
violet; and a first wavelength converting layer configured to
absorb at least a portion of the radiation emitted by the first
plurality of radiation sources, the first wavelength converting
layer having an emission wavelength ranging from about 420 nm to
about 520 nm.
2. The LED lamp of claim 1, wherein the first wavelength is in a
first range from about 380 nm to about 435 nm.
3. The LED lamp of claim 1, wherein first wavelength converting
layer comprises blue-emitting down-converting materials disposed in
or on a remote structural member, the remote structural member
forming a dome.
4. The LED lamp of claim 1, further comprising an encapsulating
material overlaying the first plurality of radiation sources and
the second plurality of radiation sources, the encapsulating
material comprising a material selected from silicone, epoxy, and a
combination thereof.
5. The LED lamp of claim 1, wherein the first plurality of
radiation sources and the second plurality of radiation sources
comprises a light emitting diode.
6. The LED lamp of claim 1, wherein a ratio of m to n (m:n) is
greater than 2:1.
7. The LED lamp of claim 1, wherein a total emission color
characteristic of the LED lamp is substantially a white color.
8. The LED lamp of claim 1, wherein a ratio of m to n (m:n) is
about 3:1.
9. The LED lamp of claim 1, further comprising a rectifier
module.
10. The LED lamp of claim 1, further comprising a base.
11. The LED lamp of claim 1, wherein the first wavelength
converting layer is characterized by a relative absorption strength
of less than 50% of a peak absorption strength of the first
wavelength converting layer at the wavelength emitted by the second
plurality of radiation sources.
12. The LED lamp of claim 1, wherein the second plurality of
radiation sources is configured with an encapsulating material
comprising at least one down-converting material configured to
absorb at least a portion of the radiation emitted by the second
plurality of radiation sources.
13. The LED lamp of claim 12, wherein the at least one
down-converting material emits radiation with a wavelength longer
than about 460 nm and shorter than about 600 nm.
14. The LED lamp of claim 12, wherein the at least one
down-converting material emits radiation with a wavelength longer
than about 550 nm and shorter than about 750 nm.
15. The LED lamp of claim 12, wherein the second plurality of
radiation sources comprise k+l sources, wherein k+l=m; and the k
sources comprise an encapsulating material comprising the at least
one down-converting material that emits radiation with a wavelength
longer than about 460 nm and shorter than about 600 nm.
16. The LED lamp of claim 12, wherein the second plurality of
radiation sources comprise k+l sources, wherein k+l=m, and the l
sources comprise an encapsulating material comprising at least one
down-converting material that emits radiation with a wavelength
longer than about 550 nm and shorter than about 750 nm.
17. The LED lamp of claim 12, comprising a second down-converting
material disposed on a remote structural member.
18. The LED lamp of claim 12, comprising a second down-converting
material disposed on a portion of the lamp such that the radiation
from one of the first radiation sources and the second radiation
source is not absorbed without first undergoing either an optical
scattering or optical reflection.
19. An LED lamp comprising: a first plurality of n radiation
sources configured to emit radiation characterized by a first
wavelength, the first wavelength being substantially blue; and a
second plurality of m radiation sources configured to emit
radiation characterized by a second wavelength, the second
wavelength being substantially violet; and a first wavelength
converting layer configured to absorb at least a portion of
radiation emitted by the second plurality of radiation sources, the
first wavelength converting layer having an emission wavelength
ranging from about 500 nm to about 750 nm.
20. The LED lamp of claim 19, wherein the first wavelength
converting layer comprises down-converting materials disposed in or
on a remote structural member, the remote structural member forming
a dome.
21. An LED lamp with an outer surface having a white appearance
under ambient light, comprising: a light source; an outer surface,
the outer surface positioned to form a remote structural member; a
first wavelength converting layer disposed on the remote structural
member, the first wavelength converting layer configured to absorb
at least a portion of radiation emitted by the light source, the
first wavelength converting layer having an emission wavelength
ranging from about 420 nm to about 520 nm; and a second wavelength
converting layer disposed on the remote structural member, the
second wavelength converting layer having an emission wavelength
ranging from about 490 nm to about 630 nm.
22. The LED lamp of claim 21, wherein a first amount p of the first
wavelength converting material and a second amount q of the second
wavelength converting material are selected in a ratio p:q to
provide a white appearance under ambient light.
Description
[0001] This application is a Continuation of U.S. application Ser.
No. 13/856,613, filed on Apr. 4, 2013, which claims the benefit
under 35 U.S.C. .sctn.119(e) of U.S. Provisional Application No.
61/625,592 filed on Apr. 17, 2012, which is incorporated by
reference in its entirety.
FIELD
[0002] The present disclosure relates generally to light emitting
devices and, more particularly, to techniques for using remote blue
phosphors in lamps comprising light emitting devices.
BACKGROUND
[0003] Legacy LED light bulbs and fixtures use blue-emitting diodes
in combination with phosphors or other wavelength-converting
materials emitting red, and/or green, and/or yellow light. The
combination of blue emitting LEDs and red-emitting and green-
and/or yellow-emitting materials is intended to aggregate to
provide a spectrum of wavelengths, which spectrum is perceived by a
human as white light. However, although the resulting spectrum is
intended to be perceived by a human as white light, many human
subjects report that the light is significantly color-shifted. The
reported color shifting makes such legacy LED lamps and fixtures
inappropriate for various applications. Various attempts to improve
upon legacy techniques have proven ineffective and/or
inefficient.
[0004] Further, uses of green- and/or yellow-emitting materials in
the exterior structure of a lamp that can be seen by a user are
often regarded as undesirable, especially because the aesthetics of
interior lighting has traditionally been based on a white or
near-white exterior structure (e.g., as in the case of a legacy,
incandescent, "Edison" bulb).
[0005] In some legacy LED lamps, blue LEDs are used in conjunction
with down-converting phosphors embedded in an encapsulant, which
encapsulant is disposed directly atop or in close proximity to the
violet LEDs. However short wavelength light (e.g., blue light) is
known to degrade the materials used in encapsulants, thus limiting
the useful lifetime of the lamp.
SUMMARY
[0006] An improved approach involving the use of LEDs emitting
wavelengths other than the legacy blue-emitting LEDs is provided
herein.
[0007] In a first aspect, LED lamps are provided comprising: a
first plurality of n radiation sources configured to emit radiation
characterized by a first wavelength, the first wavelength being
substantially violet; a second plurality of m radiation sources
configured to emit radiation characterized by a second wavelength,
the second wavelength being substantially violet; and a first
wavelength converting layer configured to absorb at least a portion
of the radiation emitted by the first plurality of radiation
sources, the first wavelength converting layer having an emission
wavelength ranging from about 420 nm to about 520 nm.
[0008] In a second aspect, LED lamps are provided comprising: a
first plurality of n radiation sources configured to emit radiation
characterized by a first wavelength, the first wavelength being
substantially blue; and a second plurality of m radiation sources
configured to emit radiation characterized by a second wavelength,
the second wavelength being substantially violet; and a first
wavelength converting layer configured to absorb at least a portion
of radiation emitted by the second plurality of radiation sources,
the first wavelength converting layer having an emission wavelength
ranging from about 500 nm to about 750 nm.
[0009] In a third aspect, LED lamps with an outer surface having a
white appearance under ambient light are provided, comprising: a
light source; an outer surface, the outer surface positioned to
form a remote structural member; a first wavelength converting
layer disposed on the remote structural member, the first
wavelength converting layer configured to absorb at least a portion
of radiation emitted by the light source, the first wavelength
converting layer having an emission wavelength ranging from about
420 nm to about 520 nm; and a second wavelength converting layer
disposed on the remote structural member, the second wavelength
converting layer having an emission wavelength ranging from about
490 nm to about 630 nm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1A is a diagram illustrating an LED lamp having a base
to provide a mount point for a light source, according to some
embodiments.
[0011] FIG. 1B is a diagram illustrating construction of a
radiation source comprised of light emitting diodes, according to
some embodiments.
[0012] FIG. 1C is a diagram illustrating an optical device embodied
as a light source constructed using an array of LEDs, according to
some embodiments.
[0013] FIG. 1D is a diagram illustrating an apparatus with a
down-converting member having a phosphor mix, according to an
embodiment of the disclosure.
[0014] FIG. 1E is a side view illustrating a remote blue phosphor
dome for generating white light, according to an embodiment of the
disclosure.
[0015] FIG. 1F is a top view illustrating a chip-array-based
apparatus with phosphors disposed on a surface of a heat sink,
according to an embodiment of the disclosure.
[0016] FIG. 2A is a diagram illustrating an optical device having
phosphor materials disposed directly atop an LED device or in very
close proximity to an LED device, according to an embodiment of the
present disclosure.
[0017] FIG. 2B is a diagram illustrating an optical device having
red, green, and violet radiation sources, according to an
embodiment of the present disclosure.
[0018] FIG. 3A is a diagram illustrating a conversion process,
according to some embodiments.
[0019] FIG. 3B is a diagram illustrating a conversion process,
according to some embodiments.
[0020] FIG. 4 is a graph illustrating a light process chart by
phosphor material, according to some embodiments.
[0021] FIG. 5 is an illustration of an LED lamp comprising light
source, according to an embodiment of the present disclosure.
[0022] FIG. 6 is a diagram illustrating an optical device embodied
as a light source constructed using an array of LEDs in proximity
to remote down-converting member having a phosphor mix, according
to an embodiment of the disclosure.
[0023] FIG. 7 is a diagram showing relative absorption strengths,
according to an embodiment of the disclosure.
[0024] FIG. 8 depicts a block diagram of a system to perform
certain functions for manufacturing an LED lamp, according to an
embodiment of the disclosure.
[0025] FIG. 9A depicts a system to perform certain functions of an
LED lamp, according to an embodiment of the disclosure.
[0026] FIG. 9B depicts a spectrum of a light process in ambient
light, according to an embodiment of the disclosure.
[0027] FIG. 9C depicts a spectrum of a light process, according to
an embodiment of the disclosure.
[0028] FIG. 9D depicts a chromaticity chart, according to
embodiments of the disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0029] Various types of phosphor-converted (pc) light-emitting
diodes (LEDs) have been proposed in the past. Conventional pc LEDs
include a blue LED with various phosphors (e.g., in yellow and red
combinations, in green and red combinations, in red and green and
blue combinations). Various attempts have been made to combine the
blue light-emissions of the blue LEDS with phosphors to provide
color control.
[0030] According to some embodiments of the present disclosure, a
substantially white light lamp is formed by combining
wavelength-converting material that emits substantially blue light
(e.g., phosphors) with LEDs that emit red, green, and/or violet
(but not blue) light. In some embodiments, the combination is
provided in a form factor to serve as an LED light source (e.g., a
light bulb, a lamp, a fixture, etc.).
[0031] As disclosed herein, the use of green- and/or
yellow-emitting materials in the exterior structure of a lamp that
can be seen by a user is often regarded as undesirable, especially
because the aesthetics of interior lighting has been based on a
white or near-white exterior structure (e.g., as in the case of a
legacy, incandescent, "Edison" bulb). In addition to the
herein-described utility, one aspect that influences the design of
more desirable embodiments is a human's perception of aesthetics.
Many of the LED systems disclosed herein comprise of an LED lamp
having an exterior structure such as a "bulb", or "dome", or
encasement, or glass portion, or outer surface, etc. that, when
viewed in natural light (e.g., in sunlight, in interior lighting
settings, in ambient light, etc.) appear as a substantially white
"bulb", or "dome" or "outer surface". Still further, the use
blue-emitting wavelength-converting materials in the fabrication of
the aforementioned substantially white bulb, or dome results in
imparting optical scattering properties to the dome, such that the
dome appears as "soft white".
[0032] In addition to the aesthetics that consequently result from
the herein-described embodiments, such embodiments exhibit
exceptionally high efficiency in terms of perceived optical wattage
with respect to electrical power consumed. For example, most humans
report that perceived light output (e.g., brightness, candlepower,
lumens, etc.) is substantially more determined by the presence of
yellow and/or green light as compared to the presence of blue
light. Some human subjects report that added light in the
wavelength range of green and/or yellow is up to five times more
perceptible than is added light in the wavelength range of blue
light.
[0033] Table 1 shows an example of various LED pump and phosphor
emitting peak wavelengths that could be utilized to generate white
light according to embodiments provided by the present
disclosure.
TABLE-US-00001 TABLE 1 Yellow/ Blue Green Red Emission Peak 450 530
620 (nm) LED Pump 400-420 415-435 415-435 (nm)
[0034] In addition to the aforementioned benefits of combining
wavelength-converting material (e.g., phosphors) that emits
substantially blue light with LEDs that emit violet, and/or red,
and/or green light, it is known that longer wavelengths (e.g., red,
and/or green light) do not cause degradation of silicone and other
materials used in lamps. Thus, configuring LED lamps that avoid the
use of blue-emitting LEDs (or other short-wavelength colors) in
close proximity to any silicone encapsulants has a desirable effect
on the longevity of such LED lamps.
[0035] FIG. 1A is a diagram illustrating an LED lamp 100 having a
base to provide a mount point for a light source, according to some
embodiments. It is to be appreciated that an LED lamp 100,
according to the present disclosure, can be implemented for various
types of applications. As shown in FIG. 1A, a light source (e.g.,
the light source 142) is a part of the LED lamp 100. The LED lamp
100 includes a base member 151. The base member 151 is mechanically
connected to a heat sink 152, and the heat sink is mechanically
coupled to a remote structural member 155 (e.g., a bulb or a dome).
In certain embodiments, the base member 151 is compatible with a
conventional light bulb socket and is used to provide electrical
power (e.g., using an AC power source) to one or more radiation
emitting devices (e.g., one or more instances of light source 142).
In certain embodiments, the base member 151 is compatible with an
MR-16 socket and is used to provide electrical power (e.g., using
an AC power source) to the one or more radiation emitting devices
(e.g., one or more instances of light source 142). The base member
151 can conform to any of a set of standards for the base. For
example Table 2 gives standards (see "Designation") and
corresponding characteristics.
TABLE-US-00002 TABLE 2 Base Diameter IEC 60061-1 (Crest standard
Designation of thread) Name sheet E05 5 mm Lilliput Edison Screw
7004-25 (LES) E10 10 mm Miniature Edison Screw 7004-22 (MES) E11 11
mm Mini-Candelabra Edison (7004-6-1) Screw (mini-can) E12 12 mm
Candelabra Edison Screw 7004-28 (CES) E14 14 mm Small Edison Screw
(SES) 7004-23 E17 17 mm Intermediate Edison Screw 7004-26 (IES) E26
26 mm [Medium] (one-inch) 7004-21A-2 Edison Screw (ES or MES) E27
27 mm [Medium] Edison Screw 7004-21 (ES) E29 29 mm [Admedium]
Edison Screw (ES) E39 39 mm Single-contact (Mogul) 7004-24-A1 Giant
Edison Screw (GES) E40 40 mm (Mogul) Giant Edison 7004-24 Screw
(GES)
[0036] Additionally, the base member 151 can be of any form factor
configured to support electrical connections, which electrical
connections can conform to any of a set of types or standards. For
example Table 3 gives standards (see "Type") and corresponding
characteristics, including mechanical spacings between a first pin
(e.g., a power pin) and a second pin (e.g., a ground pin).
TABLE-US-00003 TABLE 3 Pin center to Pin Type Standard center
diameter Usage G4 IEC 60061-1 4.0 mm 0.65-0.75 mm MR11 and other
(7004-72) small halogens of 5/10/20 watt and 6/12 volt GU4 IEC
60061-1 4.0 mm 0.95-1.05 mm (7004-108) GY4 IEC 60061-1 4.0 mm
0.65-0.75 mm (7004-72A) GZ4 IEC 60061-1 4.0 mm 0.95-1.05 mm
(7004-64) G5 IEC 60061-1 5 mm T4 and T5 (7004-52-5) fluorescent
tubes G5.3 IEC 60061-1 5.33 mm 1.47-1.65 mm (7004-73) G5.3-4.8 IEC
60061-1 (7004-126-1) GU5.3 IEC 60061-1 5.33 mm 1.45-1.6 mm
(7004-109) GX5.3 IEC 60061-1 5.33 mm 1.45-1.6 mm MR16 and other
(7004-73A) small halogens of 20/35/50 watt and 12/24 volt GY5.3 IEC
60061-1 5.33 mm (7004-73B) G6.35 IEC 60061-1 6.35 mm 0.95-1.05 mm
(7004-59) GX6.35 IEC 60061-1 6.35 mm 0.95-1.05 mm (7004-59) GY6.35
IEC 60061-1 6.35 mm 1.2-1.3 mm Halogen 100 W (7004-59) 120 V GZ6.35
IEC 60061-1 6.35 mm 0.95-1.05 mm (7004-59A) G8 8.0 mm Halogen 100 W
120 V GY8.6 8.6 mm Halogen 100 W 120 V G9 IEC 60061-1 9.0 mm
Halogen 120 V (US)/230 V (7004-129) (EU) G9.5 9.5 mm 3.10-3.25 mm
Common for theatre use, several variants GU10 10 mm Twist-lock
120/230- volt MR16 halogen lighting of 35/50 watt, since mid- 2000
s G12 12.0 mm 2.35 mm Used in theatre and single-end metal halide
lamps G13 12.7 mm T8 and T12 fluorescent tubes G23 23 mm 2 mm GU24
24 mm Twist-lock for self- ballasted compact fluorescents, since
2000 s G38 38 mm Mostly used for high-wattage theatre lamps GX53 53
mm Twist-lock for puck- shaped under- cabinet compact fluorescents,
since 2000 s
[0037] FIG. 1B is a diagram illustrating construction of a
radiation source 120 comprising LED devices.
[0038] In certain embodiments, the LED devices (e.g., LED device
115.sub.1, LED device 115.sub.2) emit substantially only red and/or
green and/or violet (but not blue) light. The substantially only
red and/or green and/or violet emitting LED devices represent one
configuration, and other configurations are reasonable and
envisioned.
[0039] As shown in FIG. 1B, the radiation source 120 is constructed
on a submount 111 upon which submount is a layer of sapphire or
other optional insulator 112, upon which are disposed one or more
conductive contacts (e.g., conductive contact 114.sub.1, conductive
contact 114.sub.2), arranged in an array where each conductive
contact is spatially separated from other conductive contacts by an
isolation gap. Further disposed atop the submount or atop the
insulator are one or more deposits (e.g., deposit 153.sub.1,
deposit 153.sub.2) of wavelength-modifying material configured to
modify the color of the light generated by LED devices. Various
mixes of colors can be achieved using a deposit (e.g., deposit
153.sub.1, deposit 153.sub.2) of wavelength-modifying material
disposed in proximity to the radiation sources.
[0040] FIG. 1B shows LED devices in a linear array, however other
array configurations are possible, for example, as described
herein. As shown, atop the conductive contacts are LED devices
(e.g., LED device 115.sub.1, LED device 115.sub.2). The LED device
is but one possibility for a radiation source, and other radiation
sources are possible and envisioned, for example a radiation source
can be a laser device.
[0041] In certain embodiments, the devices and packages disclosed
herein include at least one non-polar or at least one semi-polar
radiation source (e.g., an LED or laser) disposed on a submount.
The starting materials can comprise polar gallium nitride
containing materials.
[0042] The radiation source 120 is not to be construed as
conforming to a specific drawing scale, and in particular, many
structural details are not included in FIG. 1B so as not to obscure
understanding of the embodiments. The isolation gap serves to
facilitate shaping of materials formed in and around the isolation
gap, which formation can be by one or more additive processes, or
by one or more subtractive processes, or both.
[0043] It is to be appreciated that the radiation sources
illustrated in FIG. 1B can output light in a variety of wavelengths
(e.g., colors) according to various embodiments of the present
disclosure. Depending on the application, color balance can be
achieved by modifying color generated by LED devices and/or
configuring and using wavelength-modifying material (e.g., a
phosphor material).
[0044] In certain embodiments, color balance can be achieved by
modifying the color of the light generated by LED devices by using
a deposit (e.g., deposit 153.sub.1, deposit 153.sub.2) of
wavelength-modifying material disposed in proximity to the
radiation source.
[0045] In certain embodiments, the phosphor material may be mixed
with an encapsulant such as a silicone material (e.g.,
encapsulating material 118.sub.1, encapsulating material 118.sub.2)
or other encapsulant that distributes phosphor color pixels (e.g.,
pixel 119.sub.1, pixel 119.sub.2) within a thin layer atop and/or
surrounding any one or more faces of the LED devices in the array
of LED devices. Other embodiments for providing color pixels can be
conveniently constructed using techniques that form deposits of one
or more wavelength-modifying materials.
[0046] As is known in the art, silicone degrades more quickly when
exposed to a high flux of higher-energy photons (e.g., shorter
wavelength light). Thus, embodiments that employ lower energy
radiation sources (e.g., red or green LEDs) reduce the rate of
degradation of the silicone components of an LED lamp. Embodiments
employing red and green LEDs are further discussed herein.
[0047] FIG. 1C is a diagram illustrating an optical device 150
embodied as a light source 142 constructed using an array of LED
devices (e.g., LED device 115.sub.1, LED device 115.sub.2, LED
device 115.sub.N, etc.) juxtaposed with a remotely-located instance
of a remote structural member 155, the remote structural member 155
having instances of wavelength converting materials (e.g., pixels,
deposits) distributed upon or within the volume 156 of the remote
structural member 155, which volume is bounded by a remote
structural member inner surface 161 and a remote structural member
outer surface 163, according to certain embodiments.
[0048] In addition to the wavelength converting materials
distributed upon or within the volume 156 of the remote structural
member 155, some embodiments include deposits of wavelength
converting materials (e.g., deposit 153.sub.1, deposit 153.sub.2,
deposit 153.sub.3, deposit 153.sub.4, deposit 153.sub.5, etc.)
disposed in close proximity to the LED devices. As shown,
wavelength-modifying material (e.g., deposit 153.sub.1, deposit
153.sub.2, deposit 153.sub.3, deposit 153.sub.4, deposit 153.sub.5,
etc.) can be disposed and distributed in a variety of
configurations, including being deposited in a cup structure, or
being deposited in a layer disposed atop the LED device.
[0049] Individually, and together, these color pixels modify the
color of light emitted by the LED devices. For example, the color
pixels are used to modify the light from LED devices to appear as
white light having a uniform broadband emission (e.g.,
characterized by a substantially flat emission of light throughout
the range of about 380 nm to about 780 nm), which is suitable for
general lighting.
[0050] In various embodiments, color balance adjustment is
accomplished by using pure color pixels, mixing phosphor material,
and/or using a uniform layer of phosphor over LED devices, and/or
using pixels distributed in a location substantially remote from
the LED device, For example, in various embodiments, color balance
adjustment is accomplished by using pixels (e.g., blue-emitting
pixels) distributed in a location substantially remote from the LED
devices (e.g., the blue-emitting pixels being distributed upon or
within the volume 156 of the remote structural member 155).
[0051] In certain embodiments, wavelength converting processes are
facilitated by using one or more pixilated phosphor
wavelength-modifying layers (e.g., see FIG. 1D, infra). For
example, the pixilated phosphor wavelength-modifying layers can
include color patterns. The color patterns of the phosphors
disposed within the wavelength-modifying layer may be predetermined
based on the measured color balance of the aggregate emitted light.
In certain embodiments, an absorption plate is used to perform
color correction. In some situations, the absorption plate
comprises color absorption material. For example, the absorbing
and/or reflective material can be plastic, ink, die, glue, epoxy,
and others.
[0052] In certain embodiments, the phosphor particles are embedded
in a reflective matrix (e.g., the matrix formed by conductive
contacts). Such phosphor particles can be disposed on the substrate
by deposition. In certain embodiments, the reflective matrix
comprises silver or other suitable material. Alternatively, one or
more colored pixilated reflector plates (not shown) are provided to
adjust aggregate color balance of the light emitted from LED
devices aggregated with light emitted from wavelength-modifying
materials. In certain embodiments, materials such as aluminum,
gold, platinum, chromium, and/or others are deposited to provide
color balance.
[0053] FIG. 1D is a diagram illustrating an apparatus 160 with a
down-converting member having a phosphor mix. As shown, the
down-converting member includes a plurality of wavelength-modifying
layers (e.g., wavelength-modifying layer 162.sub.1,
wavelength-modifying layer 162.sub.2), the wavelength-modifying
layers comprising phosphor materials. The phosphor materials are
excited by radiation emitted by light source 142. The combination
of the colors of the light emissions from the radiations sources
and the light emissions from the wavelength-modifying layers and
the light emissions from the blue-emitting wavelength conversion
materials disposed in or on the dome (e.g., remote structural
member 155) produce white-appearing light.
[0054] In certain embodiments, the apparatus 160 may be present in
embodiments of an LED lamp of the present disclosure. In certain
embodiments, of an LED lamp the apparatus 160 may be absent, or,
one or more layers of phosphor materials may disposed directly atop
an LED device, or otherwise overlaying an LED device in very close
proximity to the LED device. For example, an encapsulant can be
used to distribute phosphor materials within the encapsulant, and
the encapsulant can be disposed in a manner overlaying LED device,
and where the encapsulant is disposed in very close proximity to
the LED device.
[0055] FIG. 1E is a side view 180 illustrating another embodiment
having a remote blue phosphor dome for generating white light. As
shown, a light source 142 comprises radiation sources that emit
some combination of red light and green light and violet light (but
not blue light), which radiation sources are provided for radiating
light toward a dome (e.g., remote structural member 155). In this
embodiment the remote blue phosphor dome (e.g., remote structural
member 155) is shaped like a conventional light bulb, which shape
is not only aesthetically pleasing, but also the shape serves to
produce light that is substantially omni-directional in
intensity.
[0056] The combination of the colors of the light emissions from
the radiation sources produces white-appearing light. For example,
the embodiment as shown in side view 180 can comprise violet LEDs
in combination with yellow-emitting and/or green-emitting
down-converting materials as disposed in encapsulants, or as
disposed in deposits 153.sub.1 and 153.sub.2. Additionally,
blue-emitting down-converting materials disposed in or on the dome,
which blue-emitting down-converting materials absorb violet
emissions. The combination of emissions from these sources results
in an aggregate color tuning that produces a white-appearing
light.
[0057] In certain embodiments, the combination of the colors of the
light emissions from the radiations sources produces
white-appearing light. For example violet LEDs, can be configured
in combination with yellow-emitting and/or green-emitting
down-converting materials as disposed in encapsulants, and
yellow-emitting and/or green-emitting down-converting materials as
disposed in or on the dome, which yellow-emitting and/or
green-emitting down-converting materials disposed in or on the dome
can be mixed with blue-emitting down-converting materials also
disposed in or on the dome. The combination of emissions from these
sources results in an aggregate color tuning that produces a
white-appearing light.
[0058] The selected embodiments of bulbs having a remote blue
phosphor dome for generating white light are merely exemplary.
Other bulb types are envisioned and possible. Table 4 list a subset
of possible bulb types for LED lamps.
TABLE-US-00004 TABLE 4 Bulb Types for Lamps Bulb Category Type
Incandescent A-Shape Candle Bulb Globe Bulged Reflector B-Type
BA-Type G-Type J-Type S-Type SA-Type F-Type T-Type Y-Type
Fluorescent T-4 T-5 T-8 T-12 Circline ANSI ANSI C ANSI G Halogen
A-Type Aluminum Reflector Post Lamps (e.g., BT15) MR PAR Bulged
Reflector HID ED-Type ET-Type B-Type BD-Type T-Type E-Type A-Type
BT-Type CFL Single Twin Tube Double Twin Tube Triple Twin Tube
Spiral
[0059] FIG. 1F is a top view 190 illustrating a light source 142
apparatus with phosphors disposed on a surface of a heat sink. As
shown, wavelength converting materials 153.sub.1, 153.sub.2, and
153.sub.3 are disposed atop the heat sink 152.sub.2 in a pattern
around the light source 142.
[0060] FIG. 2A is a diagram illustrating an optical device 200
having phosphor materials disposed directly atop an LED device, or
in very close proximity to an LED device. In embodiments wherein
portions of the final white light spectrum are contributed by
direct emission from radiation sources, it is desirable to avoid
interaction of such direct emission with any wavelength converting
materials (e.g., down-conversion materials, phosphors,
wavelength-modifying layers, pixels, etc.). For example, for
violet-emitting radiation sources in which the emission is being
combined with other radiation sources that are pumping to longer
wavelength down-conversion media (e.g., to make broader spectrum
light), the down-conversion media can be isolated from the optical
path of the violet-emitting LEDs. And, providing such an isolation
(e.g., using an isolation barrier) increases efficiency as there
are losses (e.g., backscattered light into an LED chip) associated
with down-conversion. Instead, in certain embodiments, optical
means (e.g., an isolation barrier) are provided to reflect light
from the radiation sources toward the desired optical far-field
such that the reflected light does not substantially interact with
down-conversion media.
[0061] One such embodiment is shown in FIG. 2A. As shown, LEDs are
placed into recessed regions in a submount (e.g., substrate or
package) such that they are optically isolated from one another.
Further, light from the violet direct-emitting LEDs 203 does not
substantially interact with the encapsulated down-conversion media
and, instead, is substantially directed into the desired final
emission pattern of the entire lamp (e.g., toward the dome).
Conversely, light from the down-converted LEDs (e.g.,
down-converting LED 204.sub.1, down-converting LED 204.sub.2) is
converted locally and directed to the final emission pattern. In
addition to providing efficient light collection from the
direct-emitting LEDs, this design avoids cascading down-conversion
events (e.g., violet down-converted to green, green down-converted
to red) which can unnecessarily reduce overall efficiency since
quantum yields of down-conversion media are less than 100%.
[0062] Light from the individual LEDs are combined together in the
far field to provide a uniform broadband emission which is a
combination of light from the direct-emitting and down-converting
LED chips.
[0063] As can be appreciated, as shown in FIG. 2A the embodiment of
optical device 200 can be used in an LED lamp comprising a first
set of radiation sources configured to emit radiation characterized
by a substantially violet wavelength (e.g., violet direct-emitting
LEDs 203) and a second set of radiation sources configured to emit
radiation characterized by a second wavelength, the second
wavelength being longer than 450 nm. Further, the light emitted
from violet direct-emitting LEDs 203 and the light emitted from the
second set of radiation sources (e.g., down-converting LED
204.sub.1, down-converting LED 204.sub.2) is incident on the remote
blue phosphors in or on the dome in an LED lamp, and thus a
color-tuned (e.g., white) light is perceived.
[0064] The aforementioned remote blue phosphors can be phosphors
(see list, below) or other wavelength-modifying materials that
serve to absorb at least a portion of radiation emitted by the
first set of radiation sources.
[0065] FIG. 2B is a diagram illustrating an optical device 250
having red, green, and violet radiation sources. In the embodiment
of FIG. 2B, the same benefits pertaining to disposition of
radiation sources in proximity to isolation barriers are provided
by fabrication of the isolation barriers using an additive, rather
than subtractive, process. In an additive processes, the barrier is
formed by techniques such as overmolding,
deposition/lithography/removal, attachment of a barrier mesh, etc.
In subtractive processes, the recesses are formed by techniques
such as deposition/lithography/removal and other techniques well
known in the art. FIG. 2B shows down-convernting (rec) LED chip
204.sub.1, direct-emitting LED chip 203, down-confernting (green)
LED chip 204.sub.2 overlying a submount with barriers between the
chips.
[0066] The radiation sources can be implemented using various types
of devices, such as light emitting diode devices or laser diode
devices. In certain embodiments, the LED devices are fabricated
from gallium and nitrogen submounts, such as a GaN submount. As
used herein, the term GaN submount is associated with Group III
nitride-based materials including GaN, InGaN, AlGaN, or other Group
III containing alloys or compositions that are used as starting
materials. Such starting materials include polar GaN submounts
(e.g., submount 111 where the largest area surface is nominally an
(h k l) plane wherein h=k=0, and 1 is non-zero), non-polar GaN
submounts (e.g., submount material where the largest area surface
is oriented at an angle ranging from about 80-100 degrees from the
polar orientation described above toward an (h k l) plane wherein
l=0, and at least one of h and k is non-zero), or semi-polar GaN
submounts (e.g., submount material where the largest area surface
is oriented at an angle ranging from about +0.1 to 80 degrees or
110-179.9 degrees from the polar orientation described above toward
an (h k l) plane wherein l=0, and at least one of h and k is
non-zero).
[0067] FIG. 3A is a diagram illustrating a conversion process 300.
As shown, a radiation source 301 is configured to emit radiation at
violet, near ultraviolet, or UV wavelengths. The radiation emitted
by radiation source 301 is absorbed by the phosphor materials
(e.g., the blue phosphor material 302, the green phosphor material
303, and the red phosphor material 304). Upon absorbing the
radiation, the blue phosphor material 302 emits blue light, the
green phosphor material 303 emits green light, and the red phosphor
material 304 emits red light. As shown, a portion (e.g., portion
310.sub.1, portion 310.sub.2) of the emissions from the blue
phosphor are incident on the surrounding phosphors, and are
absorbed by the green phosphor material and red phosphor material,
which emits green and red light, respectively.
[0068] FIG. 3B is a diagram illustrating a conversion process 350.
As shown, a radiation source 351 is configured to emit radiation at
wavelengths that are shorter than wavelengths in the blue spectrum.
The radiation emitted by radiation source 351 is reflected by blue
light emitting wavelength converting material 352. And, as shown,
the radiation emitted by radiation source 353 (longer wavelengths)
is transparent to the blue light emitting wavelength converting
material 352, and the radiation emitted by radiation source 353
(longer wavelengths) passes through the blue light emitting
wavelength converting material 352.
[0069] FIG. 4 is a graph illustrating a light process chart 400 by
phosphor material. As shown in FIG. 4, radiation with a wavelength
of violet, near violet, or ultraviolet from a radiation source is
absorbed by the blue phosphor material, which in turn emits blue
light. As shown in FIG. 4, each phosphor is most effective at
converting radiation at its particular range of wavelength. And, as
shown, some of these ranges overlap.
[0070] Moreover, as shown, the absorption curves overlap the
emission curves to varying degrees. For example, the blue phosphor
absorption curve 455 overlaps the blue phosphor emission curve 456
in a wavelength range substantially centered at 430 nm. In certain
embodiments, some of the one or more LED devices that are disposed
on a light source 142 are configured to emit substantially blue
light so that the emitted blue light serves to pump red-emitting
and green-emitting phosphors.
[0071] It is to be appreciated that embodiments of the present
disclosure maintain the benefits of UV- and/or V-pumped pcLEDs
while improving conversion efficiency. In one embodiment, an array
of LED chips is provided, and is comprised of two groups. One group
of LEDs has a shorter wavelength to enable pumping of a blue
phosphor material. The second group of LEDs has a longer wavelength
which may, or may not, excite a blue phosphor material, but will
excite a green or longer wavelength (e.g., red) phosphor material.
The combined effect of the two groups of LEDs in the array is to
provide light of desired characteristics such as color (e.g.,
white) and color rendering. Furthermore, the conversion efficiency
achieved in some embodiments will be higher than that of the
conventional approach. In particular, the cascading loss of blue
photons pumping longer-wavelength phosphors may be reduced by
localizing blue phosphor to regions near the short-wavelength LEDs.
In addition, the longer-wavelength pump LEDs will contribute to
overall higher efficacy by being less susceptible to optical loss
mechanisms in GaN, metallization, and packaging materials, as
described above.
[0072] In certain embodiments, a relatively larger number of LED
devices that emit wavelengths longer than blue are combined with a
relatively smaller number of LED devices that emit wavelengths
shorter than blue, and the combination of those radiation sources
with a blue-emitting phosphor combine to produce white light.
[0073] Any of the wavelength conversion materials discussed herein
can be ceramic or semiconductor particle phosphors, ceramic or
semiconductor plate phosphors, organic or inorganic downconverters,
upconverters (anti-stokes), nanoparticles, and other materials
which provide wavelength conversion. Some examples are listed as
follows:
[0074]
(Sr.sub.n,Ca.sub.1-n).sub.10(PO.sub.4).sub.6*B.sub.2O.sub.3:Eu.sup.-
2+ (wherein 0.ltoreq.n.ltoreq.1)
[0075]
(Ba,Sr,Ca).sub.5(PO.sub.4).sub.3(Cl,F,Br,OH):Eu.sup.2+,Mn.sup.2+
[0076] (Ba,Sr,Ca)BPO.sub.5:Eu.sup.2+, Mn.sup.2+
[0077] Sr.sub.2Si.sub.3O.sub.8*2SrCl.sub.2:Eu.sup.2+
[0078] (Ca,Sr,Ba).sub.3MgSi.sub.2O.sub.8:Eu.sup.2+, Mn.sup.2+
[0079] BaAl.sub.8O.sub.13:Eu.sup.2+
[0080] 2SrO*0.84P.sub.2O.sub.5*0.16B.sub.2O.sub.3:Eu.sup.2+
[0081] (Ba,Sr,Ca)MgAl.sub.10O.sub.17:Eu.sup.2+,Mn.sup.2+
[0082] K.sub.2SiF.sub.6:Mn.sup.4+
[0083] (Ba,Sr,Ca)Al.sub.2O.sub.4:Eu.sup.2+
[0084] (Y,Gd,Lu,Sc,La),BO.sub.3:Ce.sup.3+,Tb.sup.3+
[0085] (Ba,Sr,Ca).sub.2(Mg,Zn)Si.sub.2O.sub.7:Eu.sup.2+
[0086] (Mg,Ca,Sr, Ba,Zn).sub.2Si.sub.1-xO.sub.4-2x:Eu.sup.2+
(wherein 0.ltoreq.x.ltoreq.0.2)
[0087] CaMgSi.sub.2O.sub.6: Eu.sup.2+
[0088] (Ca, Sr, Ba)MgSi.sub.2O.sub.6: Eu.sup.2+
[0089] (Sr,Ca,Ba)(Al,Ga).sub.2S.sub.4:Eu.sup.2+
[0090]
(Ca,Sr).sub.8(Mg,Zn)(SiO.sub.4).sub.4Cl.sub.2:Eu.sup.2+,Mn.sup.2+
[0091] Na.sub.2Gd.sub.2B.sub.2O.sub.7:Ce.sup.3+,Tb.sup.3+
[0092] (Sr,Ca,Ba,Mg,
Zn).sub.2P.sub.2O.sub.7:Eu.sup.2+,Mn.sup.2+
[0093] (Gd,Y,Lu,La).sub.2O.sub.3:Eu.sup.3+,Bi.sup.3+
[0094] (Gd,Y,Lu,La).sub.2O.sub.2S:Eu.sup.3+,Bi.sup.3+
[0095] (Gd,Y,Lu,La)VO.sub.4:Eu.sup.3+,Bi.sup.3+
[0096] (Ca,Sr)S:Eu.sup.2+,Ce.sup.3+
[0097]
(Y,Gd,Tb,La,Sm,Pr,Lu).sub.3(Sc,Al,Ga).sub.5-nO.sub.12-3/2n:Ce.sup.3-
+ (wherein 0.ltoreq.n.ltoreq.0.5)
[0098] ZnS:Cu+,Cl.sup.-
[0099] (Y,Lu,Th).sub.3Al.sub.5O.sub.12:Ce.sup.3+
[0100] ZnS:Cu.sup.+,Al.sup.3+
[0101] ZnS:Ag.sup.+,Al.sup.3+
[0102] ZnS:Ag.sup.+,Cl.sup.-
[0103] (Ca, Sr) Ga.sub.2S.sub.4: Eu.sup.2+
[0104] SrY.sub.2S.sub.4:Eu.sup.2+
[0105] CaLa.sub.2S.sub.4:Ce.sup.3+
[0106] (Ba,Sr,Ca)MgP.sub.2O.sub.7:Eu.sup.2+, Mn.sup.2+
[0107] (Y,Lu).sub.2WO.sub.6:Eu.sup.3+, Mo.sup.6+
[0108] CaWO.sub.4
[0109] (Y,Gd,La).sub.2O.sub.2S:Eu.sup.3+
[0110] (Y,Gd,La).sub.2O.sub.3:Eu.sup.3+
[0111] (Ba,Sr,Ca).sub.nSi.sub.nN.sub.n:Eu.sup.2+ (where
2n+4=3n)
[0112] Ca.sub.3(SiO.sub.4)Cl.sub.2:Eu.sup.2+
[0113]
(Y,Lu,Gd).sub.2-nCa.sub.nSi.sub.4N.sub.6+nC.sub.1-n:Ce.sup.3+,
(wherein 0.ltoreq.n.ltoreq.0.5)
[0114] (Lu,Ca,Li,Mg,Y) .alpha.-SiAlON doped with Eu.sup.2+ and/or
Ce.sup.3+
[0115] (Ca,Sr,Ba)SiO.sub.2N.sub.2:Eu.sup.2+,Ce.sup.3+
[0116] (Sr,Ca)AlSiN.sub.3:Eu.sup.2+
[0117] CaAlSi(ON).sub.3:Eu.sup.2+
[0118] Sr.sub.10(PO.sub.4).sub.6Cl.sub.2:Eu.sup.2+
[0119] (BaSi)O.sub.12N.sub.2:Eu.sup.2+
[0120] M(II).sub.aSi.sub.bO.sub.cN.sub.dCe:A wherein
(6<a<8,8<b<14,13<c<17,5<d<9,0<e<2)
and M(II) is a divalent cation of
(Be,Mg,Ca,Sr,Ba,Cu,Co,Ni,Pd,Tm,Cd) and A of
(Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy, Ho,Er,Tm,Yb,Lu,Mn,Bi,Sb)
[0121] SrSi.sub.2(O,Cl).sub.2N.sub.2:Eu.sup.2+
[0122] (Ba,Sr)Si.sub.2(O,Cl).sub.2N.sub.2:Eu.sup.2+
[0123] LiM.sub.2O.sub.8:Eu.sup.3+ where M=(W or Mo)
[0124] For purposes of the application, it is understood that when
a phosphor has two or more dopant ions (i.e., those ions following
the colon in the above phosphors), this is to mean that the
phosphor has at least one (but not necessarily all) of those dopant
ions within the material. That is, as understood by those skilled
in the art, this type of notation means that the phosphor can
include any or all of those specified ions as dopants in the
formulation. Further, it is to be understood that nanoparticles,
quantum dots, semiconductor particles, and other types of materials
can be used as wavelength converting materials.
[0125] FIG. 5 is an illustration of an LED system 500 comprising an
LED lamp 510, according to some embodiments. The LED lamp 510 is
configured such that the total emission color characteristic of the
LED lamp is substantially white in color.
[0126] The LED system 500 is powered by an AC power source 502, to
provide power to a rectifier module 516 (e.g., a bridge rectifier)
which in turn is configured to provide a rectified output to an
array of radiation emitting devices (e.g., a first array of
radiation emitting devices, a second array of radiation emitting
devices) comprising a light source 142. A control module 505 is
electrically coupled to the first array and second array of
radiation emitting devices; and a signal compensating module 514
electrically coupled to the control module 505, the signal
compensating module being configured to generate compensation
factors based on the signaling of the control module. As shown, the
rectifier module 516 and the signal compensating module (and other
components) are mounted to a printed circuit board 503. Further,
and as shown, the printed circuit board 503 is electrically
connected to a power pin 515 mounted within a base member 151, and
the base is mechanically coupled to a heat sink 152.
[0127] The embodiments disclosed herein can be operated using
alternating current that is converted to direct current (as in the
foregoing paragraphs), or can be used using alternating current
without conversion. Some embodiments deliver DC to power pin
515.
[0128] FIG. 6 is a diagram illustrating an optical device embodied
as a light source constructed using an array of LEDs in proximity
to remote down-converting member having a phosphor mix, according
to certain embodiments of the disclosure.
[0129] As shown, the embodiment of FIG. 6 depicts an LED lamp
comprising a light source 142, which light source is formed of an
array having a first plurality of "n" of radiation sources
configured to emit radiation characterized by a first wavelength,
the first wavelength being substantially violet, and a second
plurality of "m" of radiation sources configured to emit radiation
characterized by a second wavelength, the second wavelength being
substantially violet. The remote structural member 155 serves to
support a wavelength converting layer configured to absorb at least
a portion of radiation emitted by the first plurality of radiation
sources, where the wavelength converting layer has a wavelength
emission ranging from about 420 nm to about 520 nm. As shown in
FIG. 6, remote structural member 155 includes remote structural
member outer surface 163, volume 156, and remote structural member
inner surface 161.
[0130] In some embodiments, the wavelength converting layer
comprises one or more of the following: [0131] (Ca, Sr,
Ba)MgSi.sub.2O.sub.6: Eu.sup.2+ [0132]
Ba.sub.3MgSi.sub.2O.sub.8:Eu.sup.2+ [0133]
Sr.sub.10(PO.sub.4).sub.6C.sub.12:Eu.sup.2+
[0134] In certain embodiments, LED lamp comprises "n" radiation
sources configured to emit radiation characterized by a range of
about 380 nm to about 435 nm. Further, certain embodiments are
configured such that the wavelength converting layer comprises
blue-emitting down-converting materials disposed in or on the
remote structural member (as shown, the remote structural member
forms a dome).
[0135] The light source 142 can comprise radiation source
encapsulating material (e.g., encapsulating material 602.sub.1,
encapsulating material 602.sub.2) that overlays at least some of
the first plurality of radiation sources and possibly the second
plurality of radiation sources, where the encapsulating material
comprises silicone and/or epoxy material, and where at least some
of the down-converting material serves to absorb radiation emitted
by the second plurality of radiation sources. Of course, the number
"m" and the number "n" can be varied such that a ratio (m:n)
describes the relative mix of the radiation sources. For example,
the ratio of the number m to the number n (m:n) can be greater than
the ratio 2:1. Or, strictly for example, the ratio of the number m
to the number n (m:n) is about 3:1. In various configurations as
depicted in FIG. 7, the total emission color characteristic of the
LED lamp is substantially white in color.
[0136] In certain embodiments, the wavelength converting layer as
is distributed upon or within the volume and has a relative
absorption strength of less than 50% of a peak absorption strength
of the first wavelength converting layer when measured against the
wavelength emitted by the second plurality of radiation
sources.
[0137] Other configurations are reasonable and envisioned. For
example: [0138] configurations where the down-converting material
emits radiation with a wavelength longer than about 460 nm and
shorter than about 600 nm. [0139] configurations where
down-converting material disposed on the m radiation sources emits
radiation with a wavelength longer than about 550 nm and shorter
than about 750 nm. [0140] configurations where the m radiation
sources consist of k and l sources such that k+l=m, and the k
sources have an encapsulating material [0141] configurations where
an additional down-converting material is disposed in or on the
remote structural member (e.g., other than blue-emitting
down-converting material).
[0142] In certain configurations down-converting material is
disposed on a portion of the lamp such that the radiation from
either the m or n radiation sources is not absorbed without first
undergoing either an optical scattering or optical reflection. It
is also possible that the down-converting material (e.g., the
additional down-converting material) is substantially excited by
the first down-converting material disposed on the remote
structural member.
[0143] Even still more light process can occur within the practice
of the embodiments, namely, processes where the additional down
converting materials have a peak emission wavelength ranging from
about 580 nm to about 680 nm. And/or where the down-converting
material has an emission full-width at half maximum spectra less
than about 80 nm, and/or where the down-converting material has an
emission full-width at half maximum spectra less than about 60 nm,
or less than about 40 nm.
[0144] The down-converting material can comprise down-converting
material in the form of a quantum dot material.
[0145] Other configurations of the LED lamp are possible including
embodiments where a first plurality of n of radiation sources are
configured to emit radiation characterized as being substantially
blue; and a second plurality of m of radiation sources are
configured to emit radiation characterized as being substantially
violet, and further, where a first wavelength converting layer is
configured to absorb at least a portion of radiation emitted by the
second plurality of radiation sources, while the first wavelength
converting layer has a wavelength emission ranging from about 500
nm to about 750 nm.
[0146] FIG. 7 is a diagram 700 showing a relative absorption
strength based on measured intensity (e.g., intensity ordinate 710)
as a function of wavelength (e.g., wavelength abscissa 720) for a
particular spectrum range of light. A relative absorption strength
of 50% of a peak absorption strength is shown as covering a range
of wavelengths ("P", as shown) centered about a given peak
wavelength (e.g., peak 730).
[0147] FIG. 8 depicts a block diagram of a system to perform
certain functions for manufacturing an LED lamp. As an option, the
present system 800 may be implemented in the context of the
architecture and functionality of the embodiments described herein.
Of course, however, the system 800 or any operation therein may be
carried out in any desired environment. The modules of the system
can, individually or in combination, perform manufacturing method
steps within system 800. Any method steps performed within system
800 may be performed in any order unless as may be specified in the
claims. As shown, FIG. 8 implements a process for manufacturing an
LED lamp comprising: providing a first plurality of n of radiation
sources configured to emit radiation characterized by a first
wavelength, the first wavelength being substantially violet (see
step 810), providing a second plurality of m of radiation sources
configured to emit radiation characterized by a second wavelength,
the second wavelength being substantially violet (see step 820),
and providing a first wavelength converting layer configured to
absorb at least a portion of radiation emitted by the first
plurality of radiation sources, the first wavelength converting
layer having a wavelength emission ranging from about 420 nm to
about 520 nm (see step 830).
[0148] FIG. 9A depicts a system 900 to perform certain functions of
an LED lamp. As an option, the present system 900 may be
implemented in the context of the architecture and functionality of
the embodiments described herein. Of course, however, the system
900 or any operation therein may be carried out in any desired
environment.
[0149] As shown in FIG. 9A, blue-emitting down-converting materials
are disposed on the remote structural member outer surface 163 or
within the volume 156 of the remote structural member forming a
dome. And, as shown, yellow-emitting wavelength-converting
materials are disposed on a remote structural member inner surface
161. Accordingly, the appearance of the dome as viewed in natural
light (e.g., sunlight) would be substantially white or cool white.
The wavelength converting processes for producing substantially
white or cool white color under ambient light conditions are
depicted as cool white spectrum 910 in FIG. 9B, according to
certain embodiments.
[0150] In operation (e.g., when the light source is on), the light
source 142 produces incident light from active LEDs (see light
source emission spectrum 144), a first portion of the LED emission
spectrum incident light is down-converted by the blue-emitting
down-converting materials disposed in or on the dome, and a second
portion of the incident light is down-converted by yellow-emitting
wavelength-converting materials disposed the remote structural
member inner surface 161. The combination of the emitted light from
the light source 142 and emitted light from the down-converting
materials combines to produce a white-appearing light (e.g., the
warm white spectrum 920 of FIG. 9C, or the LED lamp emission
spectrum, as shown in FIG. 9D).
[0151] As disclosed herein, the combination of the colors of the
light emissions from the radiations sources and from the
wavelength-converting materials produce white-appearing light when
the LED lamp is in operation. And, the combination of
yellow-emitting and/or green-emitting down-converting materials
with blue-emitting down-converting materials on the remote
structural member results in an aggregate color tuning that
contributes to a white-appearing shade when the LED lamp is not in
operation. The whiteness can be tuned by selecting the types and
proportions of the yellow-emitting and/or green-emitting
down-converting materials with respect to the blue-emitting
down-converting materials, and/or with respect to other
wavelength-converting materials, including red-emitting
down-converting materials.
[0152] For example, an LED lamp can be configured such that a first
amount p of first wavelength converting material is selected and a
second amount q of second wavelength converting material is
selected such that the total amount and ratio (first amount
p:second amount q) are sufficient to provide a white shade under
natural light. Moreover, the same amount and ratio (first amount
p:second amount q) serves to provide an LED lamp emission that has
a warm white emission spectrum when combined with the LED source
emission internal to the lamp (e.g., emissions from the light
source 142). The warm white emission spectrum is exemplified in the
warm white spectrum 920 as shown in FIG. 9C.
[0153] FIG. 9D depicts a chromaticity chart 960. The figure depicts
black body loci (also called Planckian loci), which black body loci
represent colors (as shown) through a range from deep red through
orange, yellowish white, warm white, white, and cool white.
[0154] At least some of a range of shades throughout the black body
loci are tunable by the relative measures of colors (e.g., red,
green/yellow, blue). In the disclosed embodiments of LED lamps,
color tuning to achieve a particular (e.g., desired) white shade of
the LED lamp under conditions of ambient lighting can be
accomplished by selecting the relative amounts of
wavelength-emitting materials. Similarly, when those relative
amounts of wavelength-emitting materials are excited by the light
source 142, the aggregate LED lamp emission corresponds to a
particular (e.g., desired) white light color, such as depicted by
the warm white lamp emission spectrum (as shown).
[0155] As one specific example, an LED lamp can be configured to
achieve a particular white shade by selecting a first amount p of
first wavelength converting material (e.g., a blue phosphor) and
selecting a second amount q of second wavelength converting
material (e.g., a yellow phosphor). In certain cases, a third
wavelength converting material (e.g., a red phosphor) can be mixed
in to achieve the desired tunable white shade. The amounts p and q
are selected to achieve (1) the desired (e.g., cool white) shade of
the LED lamp under ambient light conditions, and (2) the desired
LED lamp emission spectrum when the LED lamp is in operation (e.g.,
when the light source is on and its emission is combined with the
remote phosphor emission).
[0156] In certain embodiments, various pattern and/or arrangement
for different radiation sources can be used. The above description
and illustrations should not be taken as limiting the scope of the
present disclosure which is defined by the appended claims.
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